Using the desktop environment in RHEL 8

Procedure

1. Open GNOME Software.

   

2. Go to Graphics & Photography.

3. Browse the available tools, such as the following:

   Photos

   For accessing, organizing and sharing your photos.

   GNU Image Manipulation Program

   For creating images and editing photographs.

   Inkspace

   For creating and editing scalable vector graphics images.

   XSane

   For scanning images with a scanner.

   LibreOffice Draw

   For create and editing drawings, flow charts, and logos.

Procedure

1. Open Tweaks.

   The Tweaks tool

   

2. Select the item that you want to customize in the left side bar.

   For example, you can set applications to start automatically when you log in by using the Startup Applications menu, or you can customize your top bar appearance by using the Top Bar menu.

   Customizing startup applications in Tweaks

   

   Customizing the appearance of your top bar in Tweaks

   

Procedure

1. Open the /usr/share/gnome-shell/modes/classic.json file as the root user.

2. Find the following line in the file:

   "hasOverview": false

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3. Change the line to the following:

   "hasOverview": true

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4. Save changes, and close the /usr/share/gnome-shell/modes/classic.json file.
5. Restart the user session.

Verification

1. In your GNOME Classic session, open multiple windows.
2. Press the Super key to open the window overview.

3. In the overview, check that:

   • The Dash (the vertical panel on the left side of the screen) is displayed.
   • The bottom panel is not displayed.

   • The workspace switcher is displayed on the right side of the screen.

     Window overview with "hasOverview": true

     

   With the default settings ("hasOverview": false), the overview has the following features:

   • The Dash is not displayed.

   • The bottom panel is displayed. It includes the Window picker button in its left part and the workspace switcher in its right part.

     Window overview with "hasOverview": false

     

Procedure

1. From the login screen (GDM), click the gear button next to the Sign In button.

   Note

   You cannot access this option from the lock screen. The login screen appears when you first start Red Hat Enterprise Linux 8 or when you log out of your current session.

   

2. From the drop-down menu that appears, select the option that you prefer.

   Note

   Note that in the menu that appears on the login screen, the X.Org display server is marked as X11 display server.

Procedure

1. Launch the GNOME Software application.

2. Find the application to be installed in the available categories:

   • Audio & Video
   • Communication & News
   • Productivity
   • Graphics & Photography

   • Add-ons

     Add-ons include for example GNOME Shell extensions, codecs, or fonts.

   • Developer Tools
   • Utilities

   

3. Click the selected application.

   

4. Click the Install button.

   

Procedure

1. Try opening a file that is associated with an application that is currently not installed on your system.
2. GNOME automatically identifies the suitable application that can open the file, and offers to download the application.

Procedure

1. Download the required RPM package.

2. In the Files application, open the directory that stores the downloaded RPM package.

   Note

   By default, downloaded files are stored in the /home/user/Downloads/ directory.

3. Double-click the icon of the RPM package to install it.

Procedure

1. Open the Activities Overview screen.

2. Start typing the name of the required application in the search entry.

   

   GNOME automatically finds the application in a repository, and displays the application’s icon.

3. Click the application’s icon to open GNOME Software.

   

4. Click the icon of the application again.

   

5. Click Install to finish the installation in GNOME Software.

Procedure

1. Open the system menu, which is accessible from the upper-right screen corner, and click the Settings icon.

   

2. In the Details → About section, click Register.
3. Select Registration Server.
4. If you are not using the Red Hat server, enter the server address in the URL field.
5. In the Registration Type menu, select Activation Keys.

6. Under Registration Details:

   • Enter your activation keys in the Activation Keys field.

     Separate your keys by a comma (,).

   • Enter the name or ID of your organization in the Organization field.
7. Click Register.

Procedure

1. Open the system menu, which is accessible from the upper-right screen corner, and click the Settings icon.

   

2. In the Details → About section, click Details.

   The Registration Details screen appears.

3. Click Unregister.

   A warning appears about the impact of unregistering the system.

4. Click Unregister.

Procedure

1. Identify the GSettings schemas, keys, and allowed values of the settings that you want to configure.

   You cna either use the dconf editor application or the gsettings utility. For details on gsettings, see Working with GSettings keys on command line.

2. Ensure that the /etc/dconf/profile/user configuration file enables the user profile:

   user-db:user
   system-db:local

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3. Create a plain text keyfile for the default settings in the /etc/dconf/db/local.d/ directory.

   Choose a file name that represents the settings. The file name usually starts with a number, such as /etc/dconf/db/local.d/01-background.

4. In the keyfile, specify the default settings in the following format:

   [path/to/schema]
   key-name=value
   another-key-name=another-value

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   Important

   Separate the schema components with a slash (/), not a dot (.) here.

   Example 6.2. A default background

   For example, to set a default desktop background, specify the following configuration in /etc/dconf/db/local.d/01-background:

   [org/gnome/desktop/background]
   picture-uri='file:///usr/local/share/backgrounds/wallpaper.jpg' 

   1

   
   picture-options='scaled' 

   2

   
   primary-color='000000' 

   3

   
   secondary-color='FFFFFF' 

   4

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   1

   URI to use for the background image. Note that the backend only supports local file:// URIs.

   2

   Determines how the image set by wallpaper_filename is rendered.

   3

   Left or Top color when drawing gradients, or the solid color.

   4

   Right or Bottom color when drawing gradients, not used for solid color.

5. Update the system databases:

   # dconf update

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6. The user must log out and log in again for the changes to take effect.

Procedure

1. Create the /etc/dconf/db/local.d/locks/ directory.
2. In this directory, add any number of files listing keys that you want to lock.

Procedure

1. Add the following line to the beginning of the /etc/dconf/profile/user file. If the file does not exist, create it.

   service-db:keyfile/user

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   With this setting, dconf polls the keyfile back end to determine whether updates have been made, so settings might not be updated immediately.

2. The changes take effect when the users logs out and in.

Procedure

1. Create the /usr/share/mime/packages/application-x-newtype.xml file with following content:

   <?xml version="1.0" encoding="UTF-8"?>
   
   <mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
     <mime-type type="application/x-newtype">
       <comment>new mime type</comment>
       <glob pattern="*.xyz"/>
     </mime-type>
   </mime-info>

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   The sample application-x-newtype.xml file here defines a new MIME type application/x-newtype and assigns file names with the .xyz extension to that MIME type.

2. Create a new .desktop file named, for example, myapplication1.desktop in the /usr/share/applications/ with following content:

   [Desktop Entry]
   Type=Application
   MimeType=application/x-newtype
   Name=My Application 1
   Exec=myapplication1 field_code

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   The sample myapplication1.desktop file here associates the application/x-newtype MIME type with an application named My Application 1. It is run by a command myapplication1.

   Based on how myapplication1 gets started, choose one respective field code from Desktop Entry Specification. For example, for an application capable of opening multiple files, use:

   Exec=myapplication1 %F

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3. As a root user, update the MIME database for your changes to take effect.

   # update-mime-database /usr/share/mime

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4. As a root user, update the application database.

   # update-desktop-database /usr/share/applications

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Verification

1. To verify that you have successfully associated *.xyz files with the application/x-newtype MIME type, first create an empty file, for example test.xyz and execute the following commands:

   $ touch test.xyz
   
   $ gvfs-info test.xyz | grep "standard::content-type"
     standard::content-type: application/x-newtype

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2. To verify myapplication1.desktop is correctly set as the default registered application for the application/x-newtype MIME type, execute following command:

   $ gio mime --query application/x-newtype
   Default application for 'application/x-newtype': myapplication1.desktop
   Registered applications:
   	myapplication1.desktop
   Recommended applications:
   	myapplication1.desktop

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Procedure

1. Create the ~/.local/share/mime/packages/application-x-newtype.xml file with following content:

   <?xml version="1.0" encoding="UTF-8"?>
   <mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
     <mime-type type="application/x-newtype">
       <comment>new mime type</comment>
       <glob pattern="*.xyz"/>
     </mime-type>
   </mime-info>

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   The sample application-x-newtype.xml file here defines a new MIME type application/x-newtype and assigns file names with the .xyz extension to that MIME type.

2. Create a new .desktop file named, for example, myapplication1.desktop, and place it in the ~/.local/share/applications/ directory with following content:

   [Desktop Entry]
   Type=Application
   MimeType=application/x-newtype
   Name=My Application 1
   Exec=myapplication1 field_code

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   The sample myapplication1.desktop file above associates the application/x-newtype MIME type with an application named My Application 1. It is run by a command myapplication1.

   Based on how myapplication1 gets started, choose one respective field code from Desktop Entry Specification. For example, for an application capable of opening multiple files, use:

   Exec=myapplication1 %F

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3. Update the MIME database for your changes to take effect:

   $ update-mime-database ~/.local/share/mime

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4. Update the application database:

   $ update-desktop-database ~/.local/share/applications

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Verification

1. To verify that you have successfully associated *.xyz files with the application/x-newtype MIME type, first create an empty file, for example, test.xyz and execute the following commands:

   $ touch test.xyz
   
   $ gvfs-info test.xyz | grep "standard::content-type"
     standard::content-type: application/x-newtype

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2. To verify that myapplication1.desktop is correctly set as the default registered application for the application/x-newtype MIME type, execute following command:

   $ gio mime --query application/x-newtype
   Default application for 'application/x-newtype': myapplication1.desktop
   Registered applications:
   	myapplication1.desktop
   Recommended applications:
   	myapplication1.desktop

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1. /usr/share/applications/
2. /etc/xdg/
3. ~/.local/share/application/

1. mimeapps.list
2. gnome-mimeapps.list

Procedure

1. Consult the /usr/share/applications/mimeapps.list file to determine the MIME types for which you want to change the default registered application. For example, the following sample of the mimeapps.list file specifies the default registered application for the text/html and application/xhtml+xml MIME types:

   [Default Applications]
   text/html=firefox.desktop
   application/xhtml+xml=firefox.desktop

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   This example above specifies default application (Mozilla Firefox) by specifying its corresponding .desktop file (firefox.desktop). You can find .desktop files for other applications in the /usr/share/applications/ directory.

2. Create the /etc/xdg/mimeapps.list file and specify the MIME types and their corresponding default registered applications in this file.

   [Default Applications]
   text/html=myapplication1.desktop
   application/xhtml+xml=myapplication2.desktop

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   This example above sets the default registered application for the text/html MIME type to myapplication1.desktop and application/xhtml+xml MIME type to myapplication2.desktop.

Procedure

1. Consult the /usr/share/applications/mimeapps.list file to determine the MIME types for which you want to change the default registered application. For example, the following sample of the mimeapps.list file specifies the default registered application for the text/html and application/xhtml+xml MIME types:

   [Default Applications]
   text/html=firefox.desktop
   application/xhtml+xml=firefox.desktop

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   This example above specifies default application (Mozilla Firefox) by specifying its corresponding .desktop file (firefox.desktop). You can find .desktop files for other applications in the /usr/share/applications/ directory.

2. Create the ~/.local/share/applications/mimeapps.list file and specify the MIME types and their corresponding default registered applications in this file.

   [Default Applications]
   text/html=myapplication1.desktop
   application/xhtml+xml=myapplication2.desktop

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   This example above sets the default registered application for the text/html MIME type to myapplication1.desktop and application/xhtml+xml MIME type to myapplication2.desktop.

Procedure

1. Create the /etc/dconf/db/gdm.d/01-override-logo configuration file with the following content:

   [org/gnome/login-screen]
   logo='/path/to/logo.png'

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   Replace /path/to/logo.png with the full path to the image file that you want to use as the login screen logo.

2. Update the system databases:

   # dconf update

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Verification

1. Log out or otherwise switch to the login screen.
2. Check if it displays the logo that you selected.

3. If the logo does not update, restart GDM:

   # systemctl restart gdm

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   Warning

   Restarting the gdm service terminates all currently running GNOME sessions of all desktop users who are logged in. This might result in users losing unsaved data.

Procedure

1. Open the Settings application from the system menu by clicking on its icon.

   

2. In Settings, choose Region & Language from the left vertical bar.

3. Click the Language menu.

   

4. Select the required region and language from the menu.

   

   If your region and language are not listed, scroll down, and click More to select from available regions and languages.

   

5. Click Done.

6. Click Restart for changes to take effect.

   

Procedure

1. Create a local database for machine-wide settings in /etc/dconf/db/local.d/00-input-sources:

   [org/gnome/desktop/input-sources]
   # Enable Ctrl-Alt-Backspace for all users
   xkb-options=['terminate:ctrl_alt_bksp']

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2. Override the user’s setting, and prevent the user from changing it in /etc/dconf/db/local.d/locks/input-sources:

   # Lock the list of enabled XKB options
   /org/gnome/desktop/input-sources/xkb-options

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3. Update the system databases for the changes to take effect:

   # dconf update

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4. Users must log out and back in again before the system-wide settings take effect.